1. Field of the Invention
The invention refers to the field of electronic reproduction technology and is directed to a device and to the operation thereof for clamping film material into an exposure trough of a reproduction apparatus operating according to the internal drum principle and for releasing the exposed film material from the exposure trough.
2. Description of the Related Art
In such an internal drum reproduction device, also referred to as an internal drum recorder or exposer, the film material is fixed at the inside surface of a stationary mount that is shaped like a half-shell or, respectively, like a cylindrical segment and that is also referred to as an exposure trough. A light beam that is modulated in brightness by an image signal is generated in a recording element, this light beam being deflected in the direction onto the exposure trough by a rotating deflection system and being guided point-by-point and line-by-line across the film material for recording information while the recording element moves in the direction of a longitudinal axis of the exposure trough. The exposed film material is then removed from the exposure trough and is further-processed.
EP-B-0 126 469 already discloses an internal drum reproduction apparatus having a device for clamping and releasing film material. In the known device, the film material is guided through the exposure trough along a conveying slot shaped like a segment of a regular cylinder whose size is somewhat greater than that of the film material to be conveyed in order to suppress excess friction, jamming problems or the like. However, problems can thereby possibly arise to the effect that the position of the film material in the exposure trough can vary slightly, namely it can lie closer to the inside or outside wall and, potentially, can also produce folds to a certain extent, this deteriorating the exposure quality. Further, the known device also does not allow a fully automatic threading of the film material into the conveying path since, given utilization of a supply cassette, the film material must first be introduced between the conveyor rollers at the apparatus side before the automatic film conveying can occur. Moreover, the film material can vary in its lateral conveying length, so that the film material can emerge in different positions at the film discharge gap.
It is an object of the invention to create a device and the operation thereof for clamping and releasing film material that allows a reliable positioning of the film material in the exposure trough.
With the present invention, a device is provided for clamping and releasing film material onto and from a stationary holder. The film material is conveyed through the holder from a film entry to a film outlet slot with a conveyor means and is also fixed on the holder during an exposure. A positioning unit provides to the film material a motion tendency which is opposite a conveying direction during clamping.